CcanDo

Smitty,Perhaps there are other options,such as mufflers,hatch pads,etc....we are tinkering with a little different muffler design, though it is premature to go into detail.

Ben,Is it possible your boat could benefit from a bit more aft CG?

Thanks for the compliment....However,everyone would surely appreciate pictures of your ballast tank and plumbing.

MadMat

Even easier way to check the balance is to lift it on a crane with strops/lifting eyes. Hang a line from the crane hook - where it lands is your centre of gravity.

502stang

Has anyone tried to hang a counter weight off the back of the transom...over the drive or something like that. It would stand to reason that the further back the weight is located the less weight that you would have to add to your boat. Like a lever. Just asking? I know that I have heard of people adding lead in the swim platform when they have those tubular add on swim platforms.

articfriends

iTrader: (1)

Thats exactly what I was thinking too,removable weight at the ttranson so that 50 or 80 lbs acts like 400 lbs in the back seat. I have established from many times of running mine fast that it likes at least 1/2 tank of gas and about 300-400 lbs in the back seat area,the problem is if I bolt weight on the transom I think my boat will act like it's got 6 people in it when I do have passengers so thats why I'm looking at a ballast bladder in the hollow area behind the motor under molded swim platform.
On a side note I took my boat to Mackinaw island 2 years ago out on the big water and we took 2 people with us and all kinds of luggage,lawn chairs,full tank of gas,a small grill,3 coolers etc. the boat was really loaded down to where it felt sorta sluggish and heavy,I didn't take it over 75 mph for fear of blowing a drive 15 miles from port out on lake Huron but we ran into 3-4 footers and the boat felt the best it ever did,it crushed thru the waves like a real offshore boat instead of bouncing in every direction like it usually does,I was thinking that must be what it feels like to drive these boats that people talk about being built like tanks and heavy like a 28 foot cig or something,Smitty

bcarpman

I wonder if anyone has tried using a wake board boat ballast bag? Wouldn't have to worry about venting it.

Also, someone mentioned getting the water from after the engine. No worries about the heat????

BenPerfected

Cat,
I am thinking we may have the CG too far aft today. The top speed is good, but I feel like we use too much tab in 3'+. In what Lake Erie calls 2-4' water at 80 MPH we are generally using the tabs at 3 positions from neutral with the the 380 tabs. The concept on why we installed the ballast tank was so we could run faster in the bumps with less tab but end up with more control...balance from the forward ballast.

Here's a good question. Should the GC be more forward to "fly" more level in 3'+ or should the GC be move aft and then control the attitude with ballast and tabs? Where is perfect? What is ideal in using tab vs. forward ballast? With BBC's and extension boxes on a 30' vee, perfect is allusive.
Steve, what is your experience...I need one more winter project!

bcarpman

I'm certainly no expert, but like I said previously, my boat absolutly runs better in the rough when the CG is forward. No amount of tab can smooth things out like two drunks passed out on the V-berth And that's on a boat that naturally runs bow down.

I don't think it has anything to do with the boat being "more level" as you say, but just with the physics of having more mass up front to force the bow through the waves instead of bouncing off them. Yes, you can try to force that to happen with tabs, but it just doesn't work the same.

I'm guessing that with more mass in the front, you could still trim to the same attitude as you normally would, and still run smoother.

CcanDo

IMHO,after the components are located and fixed in place the point which the hull will rotate about is the empty wt.CG. Then as fuel,people and gear are loaded the CG location will probably change. Hopefully,the change will leave the CG within a safe envelope.

Hydrodynamics alone,most applicable to a V hull,one can consider the wetted surface as a friction point that scrubs speed. Therefore,as the wetted surface is running just forward of the transom there should be least friction.

Trim tabs add or subtract square inches of hull surface area. Or,tabs change the hull length,down-longer and up- shorter.

Ballast water becomes a lever arm,like the playground teeter totter. At slow speed or planing the arm starts at the transom,at high speed the arm starts at the LOADED CG.

MOBILEMERCMAN

Very nice.

I remember when you were in the planning stage.

Thanks for sharing

bcarpman

That's kind of funny. Anyone else around here run in more than one set of conditions!